In a cigarette manufacturing installation, endless conveyor belts are often used for conveying tobacco. The belts are designed as flat or trough belts. Depending upon the degree of treatment or moisture in the tobacco being conveyed, the conveyor belts are more or less totally polluted during a production cycle. To clean the conveyor belts of adhering dirt or particles of tobacco, it is known, in addition to scraping the conveyor belts, to use washing installations, in which the conveyor belt is wiped or washed with the aid of a cleaning fluid.
A washing installation of this sort is disclosed German Pat. No. 29 50 346. In that patent, an endless washing belt is used, which washing belt is guided by a first roller against the circulating conveyor belt. The conveyor belt is wiped in a direction counter to the direction of conveyor belt movement. The washing belt then passes through a bottom washtub filled with cleaning fluid, and subsequently past a pressure cylinder to squeeze out excess washing fluid from the washing bath. This conventional washing installation is relatively costly, because it requires a suitable washtub which wears out relatively rapidly due to the reciprocal running path of the conveyor belt and because it requires at least two guide rollers. Since the washtub is immersed in the cleaning fluid, this member must be rather large to produce a desirable effect.
In many cases, the cleaning arrangement of German Pat. No. 29 50346 does not adequately clean the convey belt because the material stripped from the conveyor belt by the washing belt is not removed by the washing belt in a single passage through the cleaning bath. Therefore, tobacco residues can remain adherent to the washtub and an additional cleaning of the washtub is required. An additional disadvantage is that the cleaning fluid must be replaced quite frequently to avoid any additional pick-up of tobacco particles during passage through the washtub on the conveyor belt, severely limiting the effectiveness of this washing installation.
Another washing installation is disclosed in U.S. Pat. No. 4,073,376 and German Pat. No. 28 35 472. A washtub is used. However, a washing fluid does not pass through the washtub, but rather is sprayed at an acute angle with a cleaning agent. The washing belt is moistened by the intended moistening, and a certain cleaning effect occurs at the same time. This conventional device also has a spring biased squeegee roller which presses on the washing belt and removes excess fluid. This installation is relatively costly.